In the prior art, there is a motor-driven roller massage instrument of a mat type having a size as long as the whole human body. A power transmission device portion of the above motor-driven roller massage instrument has left and right roller travel guide rails respectively incorporating stainless steel belts of a size as long as the whole human body. A single drive source motor is installed on one end side of the guide rails, and a roller is mounted to the motor to mount a motor-driven roller travel belt to the roller axially. Then, a receiving box for taken-up belt and a single drive source motor are required for a set of a starting mechanism and a terminating mechanism of the roller travel belt. Therefore, a double belt structure for forward and backward traveling is applied to the roller travel belt, which needs traveling from the starting mechanism to the terminating mechanism via a turn-back mechanism (due to the use of the single motor). For that reason, a structure of a so-called double structure power transmission device of the roller travel belt has been in use. That is, the repetitive forward and backward traveling is required for the roller travel belt, whenever this roller travel belt is received in an empty box for taken-up belt after traveling from the terminating mechanism to the starting mechanism via the turn-back mechanism in succession to the above traveling.
On the other hand, there is a device having a roller massage device incorporated only in the back portion. This device is of a type, in which a longitudinally spiral shaft is mounted to the back portion, and a massaging ball roller portion is mounted pivotally to the spiral shaft to rotate massaging ball rollers vertically in cooperation with the rotation of the spiral shaft.
However, the above motor-driven roller massage instrument in the prior art requires the stainless steel belt to ensure a certain degree of strength and elasticity, since it is necessary to mount the roller travel belt of a size as long as the whole human body. The accurate installation of guide rails or the like is also required to prevent the stainless steel belt from being twisted or crossed and so on in the course of traveling, together with a large number of auxiliary portions other than the guide rails. The receiving box for taken-up belt is further required due to the application of a belt take-up mode. For that reason, there is a need for complicated, large-volume, heavyweight mechanism, resulting in an increase of manufacture cost.
Further, a product in the prior art incorporating the drive device of a roller massage instrument into the back of a chair needs to have a thick seat portion and so on, since a large-sized motor is installed in the seat portion. For that reason, the above product results in an increase in size and weight as a whole, and thus finds difficulty in movement.
In view of the above circumstances, a mechanically-simple, trouble-free, low-cost, versatile motor-driven roller massage instrument (See Japanese Patent Application Nos. 10-193605 and 10-193609) was developed by the present applicants for application to keep the ideal figure with a stretch of the line of the backbone naturally.
An object of the present invention is to provide a more simple compact roller drive device for more certain smooth driving of a motor-driven roller massage instrument than the previously applied invention, and also to provide a motor-driven roller massage instrument mounted with such a roller drive device.
[Disclosure of the Invention]
There is provided a roller drive device of a size as approximately high as the back of the human body. The roller drive device has a frame composed of a base portion and left and right edge portions standing upright from the left and right edges of the base portion, and a longitudinal guide slit is provided in each of the left and right edge portions of the frame. A shaft having a gear is mounted to each of the upper and lower ends of the frame, and a roller chain is mounted in a ring shape round the upper and lower shafts in meshing with the gears. A shaft bushing fixed to massaging ball rollers is mounted to each roller chain, and the left and right ends of the shaft bushings are mounted in the guide slits in an inserted state. With the above structure, the roller chains are moved vertically by rotation of the shafts with a drive motor, and in cooperation with the vertical movement of the roller chains, the massaging ball rollers are guided in accordance with the guide slits for vertical movement. There are also provided a motor-driven roller massage instrument and a legless chair respectively mounted with such a roller drive device.